Sub-tidal dynamics of a near-coastal zone in the north sea

Data, gathered in the North Sea some 60 km north of the Netherlands, are used to describe the regional dynamics at sub-tidal frequencies. Using a tidally averaged set of the vertically averaged horizontal momentum equations, the influence of the separate terms in these equations is investigated experimentally. The results reveal that, especially further offshore, the wind driven motion is in (near) geostrophic balance. This confirms the ability to monitor the circulation, using information on the wind field and the bottom pressure distribution, within an accuracy equivalent to an accuracy of 0.5 mb of low pass filtered bottom pressure gauge measurements.In a part of the area where the bottom topography reaches a slope of 1.2×10⁻³ and where density fronts are observed, the motion is frequently found out of geostrophic balance. The apparent imbalance can partly be attributed to ‘sub-grid’ horizontal density gradients, which are incorporated in the measured bottom pressure gradients, assuming that no sea-level adjustment occurs.     

Internal structures of the nieuwpoort bank (southern north sea)

The subbottom survey of the Nieuwpoort Banks allows recognition of 4 successive stages underlain by leper Clay: (1) The bank rests upon a sedimentary unit, at least 2 to 5 m thick, having a subhorizontal or wedge-like interior stratification. (2) This unit is cut by a subhorizontal erosive surface. (3) On top of this a first ridge, still recognizable on its interior structure and with shoreward-dipping foreset beds, developed. (4) On top of this former ridge the present-day bank was formed with shoreward-dipping foreset beds. Since the same structures are observed in the Stroom Bank, it seems likely that the above mentioned scheme can be generalized for all near-shore ridges close to the Belgian coast.     

Distribution,organic content and particle size of suspended matter in the north sea

Data on suspended matter concentrations and the organic content of the suspended matter for January 1980 showed a division in the North Sea between the southern North Sea (high suspended matter concentrations, but relatively low organic content) and the central and northern North Sea (low suspended matter concentrations, but relatively high organic content). The Skagerrak, which receives suspended matter from the southern as well as from the central and northern North Sea, took up an intermediate position.In summer suspended matter concentrations were lower than in winter but more variable, in concentration as well as in organic content, because of admixtures of particulate matter from primary production. On deposition of the suspended matter, a considerable part of the organic matter was apparently lost (in the order of 75% or more), resulting in low organic-matter concentrations of fine-grained bottom deposits.Particle-size distributions followed two main types: one (A) with a sharp peak at 30 to 100 μm, and one (B) bell-shaped with a peak at 5 to 15 μm. Type A occurred in deeper water and consisted of particles with a high organic-matter content, type B occurred in shallow areas and consisted of particles with a low organic-matter content. The suspended particles were mainly microflocs of mineral particles and organic matter. The mineral particles of both types were predominantly of 2 to 5 μm size, which was determined after oxidation of the organic matter. It is concluded that particles of type-B distributions are regularly exchanged with the bottom through deposition and resuspension, which results in low organic-matter contents and prevents the microflocs reaching large sizes. Paricles of type-A distributions, on the contrary, can reach much larger sizes, because mostly they remain in suspension and do not lose organic matter, so that they do not easily fall apart.     

Simulations of the north sea circulation,its variability,and its implementation as hydrodynamical forcing in ERSEM

The rationale is given of how the gross physical features of the circulation and the stratification of the North Sea have been aggregated for inclusion in the ecosystem box model ERSEM. As the ecosystem dynamics are to a large extent determined by small-scale physical events, the ecosystem model is forced with the circulation of a specific year rather than using the long-term mean circulation field. Especially the vertical exchange processes have been explicitly included, because the primary production strongly depends on them. Simulations with a general circulation model (GCM), forced by three-hourly meteorological fields, have been utilized to derive daily horizontal transport values driving ERSEM on boxes of sizes of a few 100 km. The daily vertical transports across a fixed 30-m interface provide the necessary short-term event character of the vertical exchange.For the years 1988 and 1989 the properties of the hydrodynamic flow fields are presented in terms of trajectories of the flow, thermocline depths, of water budgets, flushing times and diffusion rates. The results of the standard simulation with ERSEM show that the daily variability of the circulation, being smoothed by the box integration procedure, is transferred to the chemical and biological state variables to a very limited degree only.     

The measurement and interpretation of genotype-environment interactions

Summary The regression analysis developed by Finlay and Wilkinson to investigate genotype-environment interactions and to assess genotypes for their adaptation to a range of environments is reviewed. Their analysis used the mean yield of many genotypes to provide a measure of the environment; it was not measured in physical terms. To reveal aspects of their analysis it was applied to data of the response of genotypes to variation in a single precisely measured environmental factor. The conclusions were extended to consider variation in several environmental factors.The effects on the regression statistics that occur with different samples of genotypes, sub- and super-optimal environmental conditions, differences in periods of growth, changes in the scale of measurement and the occurrence of several stress factors are outlined.The study byBreese (1969) of genotype-environment interaction inDactylis glomerata is considered against a background of these effects.     

Distribution of chroococcoid cyanobacteria and size-fractionated chlorophyll a biomass in the central and southern north sea waters during June/July 1989

The spatial and vertical distribution of phycoerythrin(PE)-containing chroococcoid cyanobacteria and the contribution of the <3 μm size fraction to overall phytoplankton chlorophyll a biomass were investigated in the central and southern North Sea during June and July 1989. PE-containing chroococcoid cyanobacteria cell numbers ranged between 6×10⁵ and 4.4×10⁷ cells·dm⁻³ and was typically between 0.5×10⁷ and 3×10⁷ cells·dm⁻³, lowest numbers being recorded near the British coast in central North Sea waters. The vertical distribution of these cyanobacteria showed no evidence to suggest a preferential accumulation deep in the euphotic zone. The <3 μm size fraction accounted for 6.6 to 57.5% of the total phytoplankton chlorophyll a biomass (mean 19.7%). In general, the relative significance of the <3 μm size fraction decreased with increasing total chlorophyll a biomass.     

禾本科牧草种子的精选加工

禾本科牧草种子是牧草种子中最难加工的一种，因其果皮与种皮相粘不易分离，颖果外面的稃片多具有微毛、绒毛和细长不规则长芒，其外型多扁长，呈不规则状，这种特殊的外观特性决定了其流动性不好，加大了精选加工的难度。为了解决这一难题，我们进行了一系列的改进。下面根据我厂对禾本科牧草种子精选加工的特殊工艺，将其工艺流程图介绍如下。     

Availability of phosphorus sources for blooms of phaeocystis pouchetii (haptophyceae) in the north sea: Impact of the river rhine

The distribution and uptake of various phosphorus fractions such as soluble reactive phosphorus (SRP), enzymatically hydrolysable phosphorus (EHP) and soluble unhydrolysable phosphorus (SUP) were studied in coastal waters of the North Sea with special emphasis on those areas inhabited by dense blooms of Phaeocystis pouchetii (Hariot) Lagerheim. A comparison was made between the uptake rates of SRP and the capacity of the phytoplankton to utilize the EHP fraction as a phosphorus source. In areas not directly influenced by the discharge of the river Rhine the phytoplankton depleted the SRP down to the detection level of 0.02 μmol·dm⁻³, while the concentration of EHP was always higher. Inorganic phosphate (SRP) was rapidly assimilated by the microplankton (algae and bacteria) as measured by the uptake of ³²P-orthophosphate. Concurrently, the alkaline phosphatase activity (APA) was high and appeared to be associated with the phytoplankton mainly. The various measurements indicated that the plankton was P-limited. The calculated rate of enzymatic hydrolysis of EHP was highly variable, but could provide the cells with orthophosphate at a rate comparable with that eeasured for the direct uptake of inorganic phosphate.The diversity and availability of phosphate sources in the area near the river Rhine varied strongly. The abundant supply of phosphorus by the river to the coastal waters can cause further growth of the phytoplankton, unrestricted by nutrient limitation. Here it seemed that EHP and APA played only an insignificant role. The dominance of Phaeocystis in these coastal waters is discussed in view of its capacities to exploit transient phosphate supply.     

The processing of coconut pollen

Results of experiments on collection, viability testing, storage and dispatch of coconut pollen are given, and their relevance to the breeding of coconuts is briefly discussed.Pollen was obtained in large quantities following oven-drying of male flowers at 40° C. Viability decreased as drying time increased but viable grains were obtained in greater numbers after two days than after drying for a single day.Germination of pollen in vitro was better at 30° C and 35° C than at other temperatures tried; media with high gelatine concentrations (30%) seemed superior to those with less gelatine.For normal breeding purposes storage of pollen for two or three months is adequate. At low temperature, reliable storage in sealed ampoules for at least this period was obtained after further drying pollen over silica gel. Some samples retained good viability for considerably longer. Most samples stored over silica gel were still viable after 5 months, though viability was low. Over damp CaCl₂ considerable reduction in viability occurred during the first month but there was little further reduction at least up to 7 months after collection, and all samples were still viable after 18 months. Freeze-dried pollen in ampoules under vacuum had up to 40% viability after storage for one year.At room temperature, viability of pollen kept at controlled humidities over sulphuric acid solutions, though retained for longer periods than in an uncontrolled atmosphere, was only reliably maintained for about three weeks; some samples remained viable for longer periods. Freeze-drying was found to greatly increase the longevity of pollen kept at room temperature; freeze-dried pollen used in a trial shipment to New Guinea retained viability for four months and was successfully used in a number of controlled pollinations.     

Observations on the population dynamics of amphiura filiformis (ophiuroidea: echinodermata) in the southern north sea and its exploitation by the dab,Limanda limanda

Density and growth of an Amphiura filiformis population living at a station in the Oyster Ground (southern North Sea) were monitored during 2 successive years (1982–1984). During this period, the density of adult animals (disk size > 4 mm) was constant and they numerically dominated the 1 mm sieve fraction of the samples. The size distribution of these adults was nearly constant and year classes were not discernable among these larger individuals. Annual recruitment was observed, but growth and survival rates of juveniles were low. During their first year, the disk size of recruits increased from 0.3 to 1.2 mm, and to 2.2 mm in their second year. Approximately 10% of the recruits of the 1982 year class survived the first 8 months. Of the recruits of the 1983 year class only 3% survived after 9 months. Consequently, the contribution by juveniles to the annual production of body tissue was small during the observation period.Adult somatic growth could not be assessed due to the apparent lack of disk growth. Regenerating arms, however, were very common among the larger individuals. Only 4% of the individuals in a sample had intact arms, whereas 55% of the animals (or 20% of all arms) had one or more ‘recent’ distal regenerations distinguishable by their smaller diameter. These regenerations presumably account for a large part of the annual growth and somatic production.Stomach content analysis of demersal fish in this area suggests that Amphiura arms form an important part of the diet of the dab, Limanda limanda. Annual consumption of Amphiura arms by dab was estimated to be 0.84 g wet weight-m⁻², which is equivalent to 420 arms or 6% of the arm population. Considering the large number of adult animals in the population and regeneration capabilities of the species, the grazing by dab will have only little if any effect on the population.     

我国油菜种子加工技术

在油菜收获后其种子经过加工处理,对来年实现增产、增收具有重要作用,而油菜种子质量也是决定油菜发芽率、高产出率的重要因素之一。本文在介绍油菜种子特性及加工工艺流程的基础上,针对油菜种子加工过程中的预清选、干燥、清选、包衣/丸化和计量包装等工序展开初步探讨。     

论建立玉米种子加工中心的必要性

1建设玉米种子加工中心是制种发展的要求甘肃省酒泉地区气候干燥,土壤肥力高,灌溉条件良好,是玉米制种的最佳地区之一。玉米杂交种制种面积逐年扩大,1999年为0.392万公顷,产种量相当于酒泉地区1.87万公顷玉米生产用种的20倍2000年玉米制种面积达到0.69万公顷;近期目标为万公顷,年产种5万吨。随着制种业的发展,玉米种子加工远远不能满足种子经营规模的日益扩大和种子质量越来越高的要求。现已建成的0.5万吨种子加工中心的种子精加工能力仅相当于种子基地建设目标2万公顷的5%,并且大部分仍以20世纪60年代就采用的谷物清选机进行初加工,起点低…     

中国东北三省粮食生产的态势、优势、问题与对策

在分析2004年东北三省农业总体概况的基础上，通过对中国东北地区黑、吉、辽三个省1980—2004年间粮食生产态势、粮食生产的比较优势等问题的研究，找出影响东北地区粮食生产的主要问题，并提出了积极的解决对策。     

The sea beet source of resistance to multiple species of root-knot nematode

Development of commercially available host-plant resistance to Meloidogyne spp. is essential to sugarbeet (Beta vulgaris L.) root-knot nematode resistance breeding. Reactions of seedlings from resistant crosses and hybrid derivatives were evaluated against juvenile (J2) inoculations in the greenhouse. The noncultivated sea beet [B. vulgaris ssp. maritime (L.) Arcang] source of resistance is effective against the four economically important root-knot nematodes, i.e., M. incognita Races 1, 2 and 4 (Race 3 not tested), M. Javanica, M. arenaria Races 1 and 2, and M. hapla. In monoxenic culture, M. arenaria inoculations resulted in the most galling, and M. hapla, the least. Species combinations induced higher rates of infection. Different races of the same Meloidogyne species caused similar galling. Preliminary inoculation studies indicated that resistance was also effective to M. Chitwoodi and M. fallax. The trait of resistance to multiple Meloidogyne species may be valuable in developing sugarbeet, and possibly transgenic lines of other crops, resistant to root-knot nematode. This revised version was published online in July 2006 with corrections to the Cover Date.     

豫北和豫中地区小麦新品种筛选与利用研究

为筛选适宜于河南省北部和中部地区种植的小麦新品种,运用灰色多维综合隶属度方法对2007-2008年度河南省小麦高肥水地冬水Ⅱ组区域试验资料进行了分析.结果表明:周麦18号、04中70、豫农416、洛麦22号和豫教0502综合性状表现较好,适于在河南省中、北部种植.同时表明,与传统的方差分析方法相比较,灰色多维综合隶属度分析方法更科学、合理,可作为小麦新品种评价的实用方法.     

Necessity of shading on north facade and optimal selection of shading device

This research is aimed at exploring the necessity of shade on the north facade and optimal selection of shading device. Firstly, the direct and diffuse solar radiation distribution on the surface of each orientation is analyzed in the air conditioning period in Shanghai and Xiamen. Secondly, the simulated building model is established to analysis the impact of different external shades on solar radiation heat gain and day-lighting with Energy-plus. These shades include fixed overhang of different dimensions, roller with different properties and louver of different slat angles. The glare index of different shade devices is also analyzed, results show that the hours exceeding the glare index set point of the fixed overhang and roller are far more than louver’s. Finally, the impact of different external shades on lighting energy consumption and air conditioning energy consumption on the north facades is analyzed. Results show that the use of medium-reflect and medium-transmit external roller is the most energy-saving in Shanghai, the effect of adjustable external blind is close to the roller, and the effect of fixed overhang is not obvious. In Xiamen, the use of adjustable external blind is the most energy-saving, the next is roller, and the last is fixed overhang. Taking energy-saving and glare into consideration, adjustable louver is the best choice of shade on the north facade in Shanghai and Xiamen.     

我国果品保鲜及加工业存在问题与发展对策

1 我国果品贮藏保鲜业面临的问题 1 1 "绿色"壁垒制约在当前国际贸易中,绿色壁垒已成为最重要的壁垒之一.我国是一个发展中国家,环境保护整体水平还比较低,果品生产与加工、包装与储运等尚存在不符合食品安全的环节,导致我国农产品的出口受阻.农药残留是长期以来困扰我国苹果和梨出口的主要因素,因农药残留和生物激素含量达不到无公害"绿色"标准而限制着我国果品的大量出口.     

我国种子加工机械市场需求的影响因素分析

目前,国产种子加工机械市场占有率低且不稳定,其主要制约因素是市场竞争机制不完善,成套设备需求不足,产品加工技术水平较低、适用性不足、发展缓慢等。因此,本文提出加强种子加工机械生产行业的管理、重视种子加工工艺与设备的研发、加强种子加工机械行业协作与联合、提高种子加工规模、促进种子加工设备成套使用、加强种子加工机械推广及应用等政策建议。     

中国北部地区极早熟玉米的生产及发展方向

极早熟玉米在我国的玉米种植全局中具有分布边远、经济价值和社会价值大等特点．在我国边远地区的经济生活中发挥着较为特殊的作用。适应社会发展的要求，极早熟玉米种植面积呈迅速扩大趋势．种植面积将由现在的33．3万hm^2左右增加到67万hm^2．针对这一情况．作者就极早熟玉米的生产状况及发展对策作了较为深入的分析和探讨。